Rowers, and propulsive Machinery, are to be fixed within the Fish, in Place of the Fins: and Goods of +greater+ Weight placed in a covered Car below: the Air-Bottle-Balloon being fixed between both. [114] And by _Kunckel’s_ or _Canton’s_ Phosphorus, See “Priestley’s History of +light+. Pages 585, 370.” [115] This was owing to the cool Air rushing in to supply the Tendency to a Vacuum by the Expansion of hot Steam, with the extricated Gass. The Accident proves that no Danger is to be dreaded from +expansion+ of the Gass. [116] From _Bersham-Forge_ near _Wrexham_, where there is always a sufficient Quantity. [117] The _detached_ Thermometer might be protected from the _Sun_, by being swung a few Inches _below_ the Car of the Balloon by means of an _Opening_ made purposely throu’ the Center of the Car. [118] _Foundation of the first Table._ (Ph. Tr. for 1777, Part 2d, Page 567.)—It was found by Experiment that the Decimal .000262 was the Expansion _on_ 30 Inches of Quicksilver, _with_ each Degree of Temperature from freezing to boiling Water: also, the Decimal .000042 was the Expansion _on_ 30 Inches of the Glass Tube (containing the Quicksilver), _with_ each Degree of ——————— Temperature: therefore by Addition, .000304 or by taking only 4 Decimals, .0003 is the Expansion _on_ 30 Inches of Quicksilver, and the Glass Tube containing it, _with_ each Degree of Temperature. _Construction of the first Table._ Thus any vertical Number, shewing the Expansion, may be readily _formed_, by _doubling_, _first_, the Number immediately under each Inch for the Expansion below it: and _afterwards_, by adding the Number immediately under each Inch, to the Expansion last found. Note: The vertical Columns, below each Inch of Quicksilver shew the Expansion _on_ that Inch, _with_ corresponding Degrees of Temperature indicated by the Thermometer in the Column to the left Hand. Example: to find the Expansion _on_ 30 Inches of Quicksilver _with_ 1 Degree of Temperature: the Answer in the Table is .003: i.e. such Expansion raises the Quicksilver the 3000th Part of an Inch. [119] There is seldom Occasion to take more than the four first Decimals out of the Table, the Remainder being of _little value_. [120] _The Foundation of the second Table._ This Table is calculated from Briggs’s Logarithms: each Number, in the second Column, being nothing more than the Logarithm—corresponding to the Point, (in the _first_ Column,) at which the Quicksilver stands in the barometric Tube,—subtracted from the Logarithm of 32 Inches multiplied by 6. _Construction of the second Table._ This Table consists of three _vertical_ Columns only: tho’ _here tripled_, for the greater Convenience of Inspection.